Washington pricing

Air Duct Replacement Cost Calculator — Washington

Estimate duct replacement cost from your home's size, run count and how hard the attic or crawlspace is to work in. Every figure below is already adjusted for Washington labor and material pricing.

Verified August 2026

Does ductwork replacement cost cost more in Washington?

+16% versus the national baseline

The State Energy Code is among the most demanding in the country and is pushing heat pumps to the default HVAC replacement, which changes both cost and rebate eligibility. Permit fees here run about 15% off the national average, and Homeowner permits allowed on owner-occupied property

Conditioned area(sq ft)

Cost per square foot($)

Supply runs

Cost per run($)

Access

Permit fee($)

Estimated total cost

$8,230 – $11,689

Cost per square foot: $5
Cost per supply run: $935

Estimates only. Local pricing, site conditions and code requirements change the real number.

What changes the number in Washington

Local cost indexAbove the national baseline	1.16x national
Permit fee index	1.15x national
Code basisStatewide code applies	Washington State Residential Code, based on the IRC, plus the State Energy Code
Owner-builder posture	Homeowner permits allowed on owner-occupied property
Largest markets	Seattle, Spokane, Tacoma, Vancouver

The formula

Cost = (sq ft x rate) + (runs x per-run cost) x access multiplier + permit

Duct replacement is priced mostly by labor hours. Tight crawlspaces and low attics can add 30–50% over an open, walkable space.

Frequently asked questions

How much does it cost to replace ductwork?

Whole-home duct replacement usually runs $3,500 to $12,000 in 2026, or roughly $2 to $4 per conditioned square foot.

Should I replace ducts with the HVAC system?

If ducts are over 20 years old, undersized or badly leaking, doing both at once saves labor and protects the new system's efficiency rating.

Sources

Sources & verification

Washington State Building Code Council

Last verified August 2026. Cost figures are modeled estimates based on national baselines adjusted for local labor and material pricing — they are not quotes. Permit rules change; confirm with the building department before starting work.